From practice, a waste paper sorting conveyor for sorting waste paper from waste cardboard is known, which comprises a row of rotatable, driven shafts mutually spaced in a conveying direction and each extending transversely to the conveying direction. The shafts each carry a row of radially extending impelling members for intermittently urging material on the sorting conveyor upward and in the conveying direction. The impellers of each of the rows are mutually spaced in longitudinal direction of the respective shaft. Rotary contours of impellers carried by each of the shafts project between rotary contours of the impellers carried by a neighboring one of the shafts.
In operation, a mixture of waste paper and waste cardboard is fed to the upstream end of the sorting conveyor. Rotary motion of the impellers intermittently urges the material on the conveyor upward and forward in conveying direction. Thus, the material on the conveyor is simultaneously shaken and transported along the conveyor. Since paper in the mixture is typically of a smaller size and more flexible than cardboard, paper on the conveyor tends to fall through interspaces between the shafts and the impellers, while cardboard tends to remain on top of the conveyor. Thus, material predominantly consisting of cardboard can be collected at the downstream end of the conveyor or succession of conveyors, and material predominantly consisting of paper can be collected from under the conveyor.
A problem of this known sorting conveyor is that in most cases it does not yield a satisfactory degree of sorting. Either too much paper is included in the sorted cardboard and/or too much cardboard is included in the sorted paper.